The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Planetary transmissions, among others, are implemented in transfer cases of all-wheel-drive vehicles to make an on-road mode and an off-road mode available.
A planetary transmission of this kind is described in EP 659 605 B1. With this planetary transmission, the cam roller is driven by the supporting shafts over a torsion spring. This serves as an energy accumulator, if the positive coupling element does not quickly locate itself in the coupled position. This construction, however, is complex, the angular position of the cylindrical cam is never exactly known, and no stop is available. Hence, the disconnection in the end position is also unreliable.
Furthermore, a planetary transmission is described in U.S. Pat. No. 5,411,110, in which a rotatable disc that forms the shift cam cooperates with a sensing member, which in turn is coupled to the coupling element via two springs. Here, the responsiveness of the interlock and the force distribution are dependent on the difference of the forces of the two springs, which suffer from tolerances.